This invention relates to an overhead traveling crane system capable of accurately controlling the position of a lifting device horizontally, the lifting device being suspended from the overhead traveling crane system so it can be elevated over a target on the ground.
First, a description will be given of an outline of an electrolysis refinery facility (see FIG. 4). An electrolytic bath 30 is a rectangular parallelepiped tank which opens upward and has a common conductor (bush bar) 32 set up on an upper surface of a side wall 30c of the electrolytic bath 30. As is most clearly shown in FIG. 3, a plurality of electrolytic baths 30 are arranged side by side longitudinally and laterally, and they come to several hundreds of tanks in total. In each electrolytic bath 30, a plurality of cathode plates K (in the case of Cu, normally between 20 and 50 plates) and a plurality of anode plates A with lugs are soaked in an electrolytic fluid alternately in parallel. Each of the cathode plates K is suspended from a cathode support bar (cross bar) 34. Both ends of the cross bar 34 as well as the lugs of the anode plates A are supported on an upper surface of one of the left and right electrolytic bath side walls 30c and the common conductor provided on the other side wall 30c, respectively. In the electric current supply of a system as shown in FIG. 3, four electrolytic baths 30 consisting of two arranged longitudinally and two arranged laterally make one set, and are wired so that electric current flows from the anode plates A to the cathode plates K. Because an electrolysis refinery power source needs low voltage and a large amount of current and has, at the same time, a wide range of voltage adjustment depending on the condition of an electrolysis operation, a semiconductor rectifier of a thyristor system or a diode system is employed.
Primary factors that hamper normal operation of the electrolysis refinery include growth of a branch shaped crystal or a nodule on the cathode plate, warping of the cathode plate, and shorting caused by a big anode fragment. For example, if a nodule grows locally on the cathode plate and hypertrophies, anode plate A and cathode plate K will short-circuit, so that the electrolysis current concentrates on the short-circuited area, and the electrolysis refinery is hampered.
Tank inspection work to discover these errors are done by workmen walking on the electrolytic baths everyday. But this demands a great deal of labor because enormous numbers of parts must be inspected and workmen walking on the electrolytic baths may cause the position of an electrode plate to shift.
Accordingly, by utilizing the fact that the gain and loss of electric current and variation in magnetic flux have a certain relationship, it is possible to measure the magnetic-flux density of the cathode plates K and/or anode plates A with a magnetic sensor and detect change of the electric current and to thus detect error on the electrode plate. Furthermore, to make the inspection work automatic and measure the magnetic-flux density, it is possible to utilize an overhead traveling crane system for salvaging electrode plates, by suspending the lifting device from it, installing a plurality of magnetic sensors on this lifting device, and placing each of the magnetic sensors adjacent to the cathode plates K and/or anode plates A supported by common conductors.
To measure the magnetic-flux density of each of the electrode plates, it is required that the overhead traveling crane system accurately positions the magnetic sensors close to the given places of the cathode plates K and anode plates A.
However, with the general-purpose model of the overhead traveling crane system, in addition to transferring error like a rail construction error or a detector error, since there is only a little space between the system and each of the electrode plates (approximately 10 cm), it would normally be difficult to operate the overhead traveling crane system to accurately position the magnetic sensor suspended from the lifting device close to the cathode plates K and/or anode plates A.
To minimize the error, it is conceivable to carry out the construction of the rail more minutely and suppress any play of oblique and lateral wheel movement to the utmost. However, in practice, it is extremely difficult to do so in a facility where the rail may be several hundred meters long.
Moreover, even if precise positioning was possible, there is a problem of the lifting device swinging by the influence of inertia caused by the traveling of the crane itself. In this case, it is conceivable to suppress swinging by fuzzy motion control or the like, but this disadvantageously causes the overhead traveling crane system to move slower and become expensive.
Therefore, this invention has an object to provide an overhead traveling crane system capable of accurately controlling the horizontal position of a lifting device installed thereon while allowing for the traveling error of the general-purpose overhead traveling crane system.
The invention aims at providing an overhead traveling crane system capable of accurately controlling the horizontal position of a lifting device while securing a large traveling rate of the general-purpose overhead traveling crane and having low installation cost.
To solve the above-mentioned problems, the invention as described herein is an overhead traveling crane system wherein a moving device is arranged so as to be movable in a horizontal direction on an upper track, and a lifting device is suspended from the moving device through a wire so as to ascend and descend, and wherein position guide means attached to the lifting device can be engaged with positioning means installed on a target on the ground so that the lifting device can be lowered and positioned after horizontal movement. Cylindrical guide members are attached to the moving device so as to extend vertically and guide bars are attached to an upper surface of the lifting device so as to extend vertically to the guide members, such that the lifting device moves substantially in only a vertical direction with respect to the moving device at the time of winding up and down the wire by inserting the guide bars into the cylindrical guide members. The lower end parts of the cylindrical guide members are expanded in a flared shape so that the upper end parts of the guide bars can be moved a little horizontally in a period between start of engagement of the position guide means with the positioning means and completion of the engagement, whereby the lifting device can be moved finely horizontally so that the position of the lifting device can be accurately controlled horizontally.
In another embodiment, the present invention is an overhead traveling crane system wherein a moving device is arranged so as to be movable in a horizontal direction on an upper track, and a suspension member is suspended from the moving device through a first wire so as to ascend and descend, and wherein a lifting device is suspended from the suspension member through a second wire so as to ascend and descend, and position guide means attached to the lifting device can be engaged with positioning means installed on a target on the ground so that the lifting device can be lowered and positioned after horizontal movement thereof. First cylindrical guide members are attached to the moving device so as to extend vertically and first guide bars are attached to an upper surface of the suspension member so as to extend vertically to the guide members, such that the suspension member moves substantially in only a vertical direction with respect to the moving device at the time of winding up and down the first wire by inserting the first guide bars into the first guide members. Second cylindrical guide members are attached to the suspension member so as to extend upright and second guide bars are attached to an upper surface of the lifting device so as to extend vertically to the guide members, wherein the lifting device moves substantially in only the vertical direction with respect to the suspension member at the time of winding up and down the second wire by inserting the second guide bars into the second guide members. The lower end parts of the second guide members are expanded in a flared shape so that upper end parts of the second guide bars can be moved a little horizontally in a period between start of engagement of the position guide means with the positioning means and completion of the engagement, whereby the lifting device can be moved finely horizontally so that the position of the lifting device can be accurately controlled horizontally.
The positioning means installed on the target on the ground may have conical engaging members on an end portion thereof, and the position guide means attached to the lifting device may have concave parts that engage with the conical engaging members so that when the lifting device is lowered after horizontal movement, the concave parts provided on the position guide means are inserted over the conical engaging members, and then the lifting device can move minutely in a horizontal direction and is thus guided in a given position and engaged therewith, so that the lifting device can be positioned.
The positioning means installed on the target on the ground may have counter-cone-shaped engaging members on an end portion thereof, and the position guide means attached to the lifting device may have convex parts engaged with the counter-cone-shaped engaging members so that when the lifting device is lowered after horizontal movement, the convex parts provided on the position guide means are inserted in the counter-cone-shaped engaging members, and then the lifting device can move minutely in a horizontal direction and is thus guided in a given position and engaged therewith, so that the lifting device can be positioned.
The position guide means may also be attached to both ends of the lifting device.
One or more magnetic sensors may be suspended from and supported by the lifting device.